Conveyer for combustion apparatus



A ug. 8, 1944. c. scHoLl.

CONVEYER FOR COMBUSTION APPARATUS Original Filed Oct. 17, 1938 C NwPatented Aug. 8, 1944 2,355,244 CONVEYER FOR COMBUSTION APPARATUS Clal'kScholl, Springfield, (Ehio, assigner to The Y Steel Products EngineeringCompany, Springfield, Ohio, a corporation of @hic Original applicationOctober 17, 1938, Serial No. 235,328. Divided and this applicationDecember. 10, 1941, Serial No. 422,1ll9

(Cl. ISB-64) 5; Claims.

Thisinvention relates .to stokers and more particularly to stokersmaking use of a Worm eed.

It is the principal object of the invention to provide a Stoker forfeeding solid fuel from a bin to a retort which is relatively light inweight, which feeds fuel at a proper controlled rate and with a minimumof crushing of the fuel, and which utilizes a minimum of power to effectthe feeding operation.

It is a further object to provide a feeding device for use with a bincontaining a quantity of solid fuel in which the feeding member may belwithdrawn from and replaced in the loaded bin for inspection or repair.

It is a further object to provide a sectional Worm shaft having auniversal coupling therein over which the fuel is adapted to be fedsubstantially without obstruction.

Itl is a still further object to provide a feeding mechanism forsupplying solid fuel to a retort and for effecting the delivery of thefuel upwardly into the retort with a minimum of churning and crushing ofthe fuel therein.

It is another object to provide a Stoker of this character which isflexible in its application so that it may be readily adapted foroperation with different sizes of furnace, different spacings from thefuel bin, and so forth.

Other objects and advantages will be apparent from the followingdescription, the accompanying drawing and the appended claims.

In the drawing Fig. 1 is a view partly in vertical section and partly inelevation showing the feeding worm extending into a bin for receivingsolid fuel;

Fig. 1a is an extension of Fig. 1 showing the retort and the drive meansfor operating the feed germ, Fig. 1a fitting on the right hand end ofis. l; i

Fig. 2 is a partial vertical sectional view through the portion of thefeeding device which is within the bin on the line 2-2 of Fig. 1;

Fig. 3 is an end elevational view of the feeding device shown in Fig. 1from the interior of the bin;

Fig. 4 is a detail lview in elevation showing a universal couplingmember for the worm shaft.

The present application is a division of application Serial No. 235,328,filed October 17, 1938.

In the feeding of solid fuel such as from a bin containing a supply ofsolid fuel into a retort, difficulty has heretofore been encountered insecuring the feeding of the fuel at a proper controlled rate, and-undersuch conditions as to avoid crushing of the fuel and the packing of theconveyer ymeans through which the fuel is fed. If the fuel is caused tobe churned or crushed during its feeding toward the retort, or if theconveyer means becomes packed or choked with fuel during the course ofthe feeding operation, an inefcient operation results, requiring the useof unnecessarily large driving forces to secure the delivery of fuel tothe retort. And even where supplied under such conditions, the crushingof the fuel tends to reduce the size unnecessarily, thereby changing thecombustion characteristics of the retort, resulting in non-uniform andless desirable operation of the retort.

In accordance with the present invention proper control of the feedingof the fuelinto the retort is secured with substantial elimination ofobjectionable churning and crushing of the fuel during the feedingoperation, and with the feeding of a proper and regulated amount ofsolid fuel into the conveyer means so that the conveyer does not becomechoked or packed with fuel but receives only that proper quantity whichcan be transmitted and conveyed readily and with a minimum usage ofpower. The invention further provides a highly flexible constructionadapted to be installed in furnaces of varying dimensions, making use ofa standard operating construction, which is simply and readily adaptedto the particular size requirements of the installation in a veryeconomical manner. The invention thus provides a highly effectiveoverall stoker installation for feeding solid fuel which is applicableto deliver solid fuel in proper condition and with a minimum powerrequirement from the bin directly into the retort.

As sometimes occurs in the course of the operation of a stoker of thischaracter, it becomes necessary to Withdraw and replace the feeding wormwithin the bin. Heretofore when such operation was required it wasusually necessary to remove a substantial portion of the solid fuel fromthe bin in order to replace the feed worm therein. However in accordancewith the present invention the entire feed worm may be easily withdrawnfrom a loaded bin, and may likewise Vbe easily replace in the loaded binWithout the necessity for removing the fuel therefrom.

Referring to the drawing which discloses a preferred embodiment of theinvention, the inner wall of the bin is shown at I0 with the feedingdevice extending adjacent such wall to provide for substantiallycomplete delivery of all of the fuel within the bin. The structure ofthe feeding device comprises a bearing member Il for receiving the wormshaft I2 and supporting the inner end thereof within the bin. Thebearing member II is formed as a section of tube or pipe welded atopposite sides to upwardly extending bracket arms I3 which in turn arebolted to a frame structure comprising angle posts lll and an invertedchannel section I5, the latter eX- tending substantially throughout thebin and toward the delivery end of the worm.

The worm shaft I2 is of substantially constant diameter throughout, andhas formed on its surface a spirally arranged conveying flight I6. Theflight I6 is of uniform pitch and also substantially uniform as regardsthickness so that the entire worm shaft is relatively of light weightand simple of manufacture.` The face of the flight is of a Varying widthso as to provide aV flight tapering in width from the inner end of thebin to the delivery end thereof. Preferably the smaller portion I1 ,ofthe flight which is received withinthe bearing II is of a constantdiameter to provide for properly guiding and supporting the inner end ofthe shaft. At the delivery end ofthe bin there is arranged a conveyertube 2U into which the shaft I2 extends, and the larger diameter portionof the ight 2l which lies within the delivery tube is likewise ofsubstantially constant diameter to provide a uniform 'feeding action forthe solid fuel as it is carried through the conveyer tube. That portionof the conveyer flight between the terminal parts I1 and 2| is of thetapering width as described, being preferably of uniformly increasingwidth of face between said two terminal portions. 'Ihe entire conveyerworm is preferably cast as an integral unit.

The worm shaft is thus exposed on its upper face to engage and deliverthe solid fuel contained within the bin. Beneath the shaft there isprovided a trough 25, either arcuate in cross section or in the form ofan open V-shaped member as shown for simplicity of manufacture, thewalls of which are spaced uniformly with respect to the flight I6. It isfound desirable to provide certain clearance between the side walls andthe flight to avoid undesired rubbing of the parts upon each other underthe shifting movement occurring in the conveyer shaft during operation,a clearance of about 1/4" at each side having been found satisfactory.The trough 25 slopes clown-- wardly in the direction of the delivery endof the conveyer, cooperating with the tapered flight on the shaft forproperly receiving and conveying the solid fuel picked up by the wormwith a `minimum of churning and crushing thereof. Such coordinatedconstruction of tapered Hight on the conveyer and the trough likewiseserves to limit the quantity of fuel transmitted by the worm and carriedthereby toward and into the conveyer tube 20, the shallower depth offace of the inner portionV of the flight avoiding the collection andmovement over the trough of an excessive quantity of fuel such as tocause packing of the conveyer and the collection of a larger quantity ofthe solid fuel at the entrance to the conveyer tube than can be properlyconveyed therethrough. Further inasmuch as the portion 2l of theconveyer flights within the conveyer tube is of larger diameter andhence of greater transmitting capacity than the tapered portion of theflight which receives the solid fuel, assurance is provided that all ofthe fuel delivered into the conveyer will be properly transmittedtherethrough without packing or collecting therein. Further the fuel isnot churned around and crushed by the exposed portion of the worm but iscaused to feed forward smoothly and easily over the trough with aminimum usage of power.

At the inlet end of the conveyer tube there is preferably provided ashear plate 21 which may Y be removed as required in order to secureaccess lll to the conveyer at thev point of entrance to the tube, suchas to remove solid objects that might be present in the solid fuel andwhich would make it impossible for the conveyer to operate. A suitableconstruction of shear plate for this purpose is shown in the patents toBurton 1,905,342 and 1,946,776 assigned to the same assignee as thisapplication. A short section of tubing 24 extends from the shear plateand receives the conveyer therein.

An additional section 25 of the conveyer tube may be provided of suchlength as required and suitably secured to the adjacent sections inorder to secure the proper length of the conveyer feed means. As will beunderstood the distance through which the conveyer must operate from abin to the furnace will vary in different installations, and it merelybecomes necessary to provide the proper length of feed worm, making useof such length of conveyer tube as required for that purpose. The retortitself is shown at 26, and a conveyer tube 21 is suitably attached tothe base 28 of the retort by means of a retaining collar 29.

In order to secure the conveyer tube 25 in feeding relation between thesections 24 and 21 a lpair of similar split clamping members areprovided which as shown comprise a lower semicylindrical half 30 intowhich the adjacent end of the conveyer tube is fastened. The top half 3|is removably fastened to the lower half by bolts 32, thus making itpossible by removing the two upper halves, to effect removal of theintermediate conveyer tube 25'. This pro-vides for withdrawal of theconveyer worm as described below.

The retort is formed with an air inlet passage 35, and with a webportion 36 which serves as a continuation of the conveyer tube throughthe base of the retort, the wall of the base Ipart being curved andopening upwardly as shown at 31 directly below the retort, to providefo-r delivery of the solid fuel thereinto. The fuel is deliveredupwardly in regulated and uniformly distributed manner between theupwardly curving walls 38 of the retort.

A second worm shaft 4I] extends through the retort, and into the tube 21adjacent the end of the shaft I2. Shaft 4l) is likewise formed with aconveying flight 4I thereon for feeding the fuel forwardly through thetube for delivery into a position beneath the retort 26. In order toprovide for the driving of shaft I2 and the relative shifting thereofwith respect to shaft 4i), a universal driving connection is providedbetween the adjacent ends of the Worm shafts I2 and 46. This member isshown at 42 as comprising a central hub portion of substantially thesame diameter as that of the two worm shafts. At each end the hub isformed with a groove 43 adapted to receive a cooperating tongue on theend of the adjacent conveyer shaft, the two grooves in the ends of themember 42 extending at right angles with respect to leach other. Bolts44 are threaded into member 42 and pass through the tongues 45 formedupon the end of the shafts, respectively, each tongue and shaft beingthus adapted to pivot with respect to hub 42 about the axis of the re-Slpective bolts, The hub portion 42 is likewise `provided with aspirally curved portion 46 which isconstructed to function as acontinuation of the night on the adjacent ends of the conveyers,

'being formed as shown to cover substantially three-.fourths of arevolution and to line up directly with the nightportions on each of theconveyor shafts. As will be clear from the drawing and from the abovedescription, there is practically no change in the effective conveyingarea of the tube as a result of the provision of such universal jointand the conveying action of the worm is thus made to progresscontinuously and uniformly substantially without interruption.

It may become necessary during the operation of the stoker to remove thec-onveying worm from the bin for repair or replacement, and theconstruction of the present invention provides for such operation in asimple manner` and without the necessity of removing the solid fuelwithin the lbin. To remove the worm, the two upper clamping members areremoved, affording access to the universal joint. Upon removal of theIbolts therefrom, the entire intermediate conveyer tube and the wormshaft may be withdrawn from the bin, the shaft being rotated if desiredto avoid as much as possible the drawing of fuel out of the bin. Toreplace the same, the shaft is merely guided into position by the trough25, meanwhile being rotated to cause the worm to thread its way into thefuel. nnal position and the two sections of the worm coupled together.

At the side of the retort opposite that through which the solid fuel isdelivered there is provided an additional tube l) which is mounted uponthe I end of the retort by means of a collar 5| in axial alignment withtube 2i and with surface 36, in position to receive the extending end ofconveyer shaft 43. A reverse flight 52 is formed upon this portion ofshaft 46, of such character as to prevent the delivery and passage offuel into the tube 50, which is thus kept substantially Aclear and freeof fuel during the operation of the device. In order to provide for theproper feeding of the fuel upwardly into the retort in uniformlydistributed manner, and to avoid unnecessary churning thereofbeneath theretort, the forward night El and the reverse night 52 terminate indennite spaced relation to the other, to the wails denning the openingin the retort and preferably in predetermined angular relationship. Withretorts of larger dimensions such as those for example for burning up to350 pounds of fuel per hour and greater, it is found that the reversenight should not extend substantially beyond the projected wall of theretort, as otherwise the uniform supply of fuel to that side of theretort is impaired. The forward feeding flight should extend into theretort a distance approximately between one-third and one-half of thelength of the retort, to secure uniformity in delivery of the fuel. Thesame general relations apply to retorts of smaller capacity, and withsuch smaller sized retorts capable of burning for example up to aboutpounds of fuel per hour, such relationship will result in the adjacentends of the forward and reverse flights terminating in such relation aste be spaced apart by a distance varying from approximately once thepitch of the flights to half the pitch of the nights. With suchrelationship, as shown in the drawing, very satisfactory delivery offuel upwardly in uniformly distributed manner into the retort is securedwith substantial reduction or elimination of objectionable crushing andchurning of the fuel beneath The tube is then clamped into the nightsand upon the wall 36 of the retort. Further in order to securesatisfactory delivery of the fuel without churning it has been founddesirable to arrange the end of the reverse flight in predeterminedphase relation with respect to the end of the forward night so as tolead the latter by approximately a quarter revolution. In thearrangement shown the forward night 4i terminates with respect to theend of the reverse night 52 at a distance approximately half of thepitch of the nights, and lagging the reverse night by approximately aquarter of a revolution.

The driving means for operating the conveyer is carried by a supportingcasting iii) against which the end of tube bilis fastened by means of aretaining collar Si. A motor bracket E2 is mounted upon upwardlyprojecting portions of the casting 6G and the drive motor S3 is arrangedto drive a reduction gear device f through a drive belt 65. Thereduction gear device is formed with a projecting driving shaft 66 whichis of non-circular cross section, and adapted to be removably receivedin driving relation with a similarly formed end collar nl integrallyformed with a connecting member Member 6E is journalled within thesupporting member Gil as shown at 69, and a thrust bearing 'lil providesfor properly taking of the thrust of the shaft through collar 6l.Suitable means comprising a washer 'H and a retaining collar i2 providedover the end of the connecting member G3 serve to prevent the access offuel, dust, and the like into bearing 69.

The end of the connecting member 68 projects into the tube 59 and isthere provided with a pivotal connection 'I3 with the end of aconnecting shaft 14, shaft 14 being thus positively rotated by theconnecting member and being capable of angular adjustment with respectthereto. Shaft 14 is pivotally connected at its opposite end with a hub15 formed upon shaft 4B, and thereby serves to transmit the drivingforce from the connecting member into the worm The construction providesfor flexibility in the arrange ment and application of the device todifferent installations, inasmuch as the driving assembly including theconnecting member S8 may be constructed as a unitary device and ofstandard dimensions, and the proper adjustment made in each case to ntthe installation by appropriately changing the length of tube 5B and ofshaft 14, such adjustment being very readily made and simply carriedout.

The invention therefore provides a highly satisfactory, simple, andlight weight, and economical stoker device for use in feeding solid fueldirectly from a bin into a retort for combustion therein. The deviceprovides for such fuel delivery in a predetermined desired quantity andunder such controlled conditions that not only is the power requiredkept within a minimum, but

` the fuel is delivered in the desired form, and withshaft havingconveyor nights thereon extending into said bin, a nat-walled V-shapedtrough positioned beneath said shaft where exposed in the bin, means forrotatably supporting one end of said Worm shaft Within said bin bycontact of the flights thereof upon the walls of said trough andproviding for free Withdrawal and replacement of the shaft along thelength of said trough, a conveyer tube extending away from said bin andreceiving the other end of said worm shaft, a second worm shaft Withinsaid tube also having a conveyor night thereon, and a universal jointnormally connecting said two worm shafts in driving relation With eachother, said universal joint providing for relative shifting in the axialalignment of said two shafts during rotation thereof and also providingfor disconnecting said worm shafts to permit withdrawal and replacevment of said nrst shaft, said universal joint being formed with acentral portion not substantially larger in diameter than said shaftsand having a portion of a night formed thereon joining and in regularcontinuation of the nights on said worm shafts to normally effectcontinuous feeding of said fuel while avoiding packing and crushing ofthe fuel at said joint.

2. A stoker of the character described adapted to feed solid fuel from abin and having a conveyer member removable from and replaceable in theloaded bin comprising a worm shaft extending into said bin and havingconveying nights thereon, the face of said nights being of uniformlytapering width increasing toward the discharge end thereof, a nat walledsubstantially V shaped trough beneath and in direct supporting relationto said flights at spaced points above the bottom of the trough andbelow and on opposite sides of the axis of said shaft, said troughsloping downwardly toward the discharge end of the bin and said slopecorresponding with the increase in width of said nights to providecontinuous support along the length of the nights with the axis of theworm shaft maintained substantially horizontal, and means located beyondthe discharge end of the bin for driving said worm shaft.

3. A stoker of the character described adapted to feed solid fuel from abin and having a conveyer member removable from and replaceable in theloaded bin comprising a worm shaft -extending into said bin and havingconveying nights thereon, the face of said nights being of uniformlytapering width increasing toward the discharge end thereof, asubstantially V shaped trough beneath and in direct supporting relationto said nights, the trough being denned by plane surfaces in directContact with said nights at spaced points above the bottom of the troughand on the opposite faces of the nights, said trough sloping downwardlytoward the discharge end of the bin to provide continuous support forthe tapering night to support the same With the worm axis located andsupported in a substantially straight line.

4. A Stoker of the character described adapted to feed solid fuel from abin and having a con- Veyer member removable from and replaceable in theloaded bin comprising a worm shaft extending into said bin and havingconveying nights thereon, the face of said nights being of uniformlytapering Width increasing toward the discharge end thereof, asubstantially V shaped trough beneath and in direct supporting relationto said nights, said nights contacting the opposite sides of said troughat spaced points above the bottom of the trough, the trough being dennedby intersecting plane surfaces and sloping downwardly toward thedischarge end of the bin to provide continuous support for the taperingnight to support the same with the Worm axis located and supported in asubstantially straight line, and means for rotatably supporting the endof the Worm located at the innermost part of the bin.

5. A Stoker of the character described adapted to feed solid fuel from abin and having a conveyer member removable from and replaceable in theloaded bin comprising a Worm shaft extending into said bin and havingconveying nights thereon, the face of said nights being of uniformlytapering width increasing toward the discharge end thereof, asubstantially V shaped trough beneath and in direct supporting relationto said nights, the trough being donned by intersecting plane surfacesand sloping downwardly toward the discharge end of the bin to providecontinuous support for the tapering night at spaced points below and onopposite sides of the axis of said shaft to support the same with theworm axis located and supported in a substantially straight line, and acylindrical conveyer tube extending in continuation of said straightline and communicating with the discharge end of said worm, the Width offace of the nights extending into said cylindrical conveyer tube beinggreater than that of the greatest diameter of the worm nights in thebin.

CLARK SCHOLL.

